This invention relates to phase-segregated polyurethanes containing certain tetraphenylboron salts as antistatic additives.
Phase-segregated polyurethanes are useful in a variety of applications such as blood bags, catheters and other medical uses, as well as for films, packaging, and the like. Because of their excellent physical properties, they would also be excellent packaging materials for devices such as electronics components. However, electronics components and similar devices are often quite sensitive to damage from static electrical discharges, and their packaging must usually have the ability to dissipate static charges. Previously known phase-segregated polyurethanes have not had the requisite antistatic behavior.
It has recently been discovered that the incorporation of certain ionizable salts into the polyurethane could improve its antistatic properties. However, the use of these salts has been limited to certain types of polyurethanes or has required the use of an enhancer compound, as described in U.S. Pat. No. 4,618,630. Although excellent antistatic properties are obtained with the use of the enhancer compounds, these compounds do tend to affect the physical properties of the polyurethane. Often, the enhancers are plasticizers which tend to decrease the tensile properties of the polyurethane and increase its elongation. This is especially true with thermoplastic polyurethanes. Accordingly, it would be desirable to provide an antistatic polyurethane, particularly a thermoplastic polyurethane, in which an enhancer compound is not required.